Tree climbing fish have split pelvic fins while land walking fish have fused pelvic fins.
Tree climbing fish have larger areas of web to ray than land walking fish.
Finite element analyses confirm that the pelvic fins of tree climbing fish are more flexible than those of land walking fish.
Tree climbing fish have frictional resistance 2.5 fold higher than land walking fish.
Pelvic fin flexibility improves lateral attachment through Stefan adhesion.